Recently, the evolutions of wireless communication systems are growing rapidly to satisfy the personal communication requirements. Compact, small size, low cost, easy fabrication, and multi-function are the major developing trends among these modern wireless communication devices. In this research, high quality Al2O3 ceramic materials are used as a substrate to fabricate modifiable dual-mode bandpass filters with the advantages of light weight, small size, and high performance. Dual mode cavity and dielectric resonator filters are the mainstay of satellite communications. In this research, a class generation of planar dual mode filters are introduced which significantly offers the advantages of small size, light weight, and low cost. The proposed bandpass filters are first simulated on Al2O3 (er=9.4) substrate for microwave frequency, and the proposed structures consist one square-typed patch, one circle-typed patch, or one meander-typed patch. Each pattern is connected with two 50£[ microstrip line, one for input and another for output. Two 50£[ microstrip lines are connected to the central of the patch with two notches, and the patch will act as the elliptic-function bandpass filters. Before the fabrication of a bandpass filter, IE3D microwave simulation software is used to simulate the designed filters. With a metal mask, the filter patterns are fabricated on the Al2O3 substrate by using evaporation method. It is found that as the length of notches increase, the three of structures band-pass filters reveal better filtering effect, i.e., the smaller insertion loss (S21), and larger return loss (S11), and the perturbation in the patch facilitates coupling between two orthogonal modes within the resonator, i.e., the perturbation size can modify bandwidth and resonator frequency. After the measurement of the fabricated filters, it is found that the measured results will match the simulated results.

<p>Each year, over 13,000 people in the United States die from a primary malignant brain tumor. Currently, primary BTs are treated most commonly by surgery, radiotherapy, and systemic chemotherapy, though each of these methods carries a risk of complications or acute side effects.</p><p>Ultrasound hyperthermia has been investigated as way to open the blood-brain barrier for improved chemotherapeutic drug delivery, but previous methods have involved either invasively removing skull bone via surgery or non-invasively dealing with the high ultrasound attenuation, reflection, and phase aberration resulting from the skull and its variable thickness. Dual-mode ultrasound transducers for image-guided therapy have also been investigated for several applications; in some instances, phased arrays are ideal, allowing control over the ultrasound energy deposition pattern and inherent spatial registration between imaging, treatment, and monitoring.</p><p>Additionally, thermosensitive liposomes can be configured to encapsulate drugs and actively target regions of tumor angiogenesis. When used in combination with localized hyperthermia, thermosensitive liposomes can provide targeted control of drug release that may enhance chemotherapeutic efficacy in many clinical settings. Meanwhile, catheter devices and endovascular techniques are used by interventional neuroradiologists to treat various intracranial diseases, including intracranial aneurysm and dural venous sinus thrombosis. These procedures can be extended to the treatment of intracranial tumors (advancement of a 5 Fr catheter as far as the frontal portion of the superior sagittal sinus has been demonstrated).</p><p>The objective of the work presented in this dissertation was the realization of a dual-mode catheter transducer for a minimally-invasive, vascular approach to deliver localized, image-guided ultrasound hyperthermia to an intracranial tumor target. Toward this end, a series of prototype ultrasound transducers were designed, simulated, built, and tested for imaging and therapeutic potential.</p><p>Two 14-Fr phased-array prototypes were built with PZT-5H ceramic and tested for real-time 3D intracranial imaging and focused-beam hyperthermia capability. These were able to visualize the lateral ventricles and Circle of Willis in a canine model, and generate a temperature rise over 4&deg;C at a 2-cm focal distance in excised tissue.</p><p>Single-channel intravascular ultrasound (IVUS) coronary imaging catheters as small as 3.5 Fr were then considered as a construction template; several possible transducer apertures were simulated before fabricating prototypes with PZT-4. The transducers exhibited a dual-frequency response, due to the presence of thickness-mode and width-mode resonances. A thermal model was developed to estimate the +4&deg;C thermal penetration depth for a given transducer aperture, predicting an effective therapeutic range of up to 12 mm with a 5 × 0.5 mm aperture.</p><p>A 3.5-Fr commercial mechanical IVUS catheter was retrofitted with a PZT-4 transducer and tested for 9-MHz imaging performance in several animal studies, successfully visualizing anatomical structures in the brain and navigating a minimally-invasive vascular pathway toward the brain. An identical PZT-4 transducer was used to build a 3.3-MHz therapy prototype, which produced a temperature rise of +13.5&deg;C at a depth of 1.5 mm in live xenograft brain tumor tissue in the mouse model.</p><p>These studies indicate that a minimally-invasive catheter transducer can be made capable of visualizing brain structures and generating localized hyperthermia to trigger drug release from thermosensitive liposomes in brain tumor tissue.</p> / Dissertation

A novel liquid sensor is designed and fabricated by using thin film bulk acoustic resonator (TFBAR) devices with c-axis 23¢X-tilted ZnO films. To fabricate TFBAR devices, the off-axis RF magnetron sputtering method for the growth of piezoelectric ZnO thin films is adopted. The influences of the relative distance and sputtering parameters are investigated. In this report, the piezoelectric ZnO thin films with tilting angle of 23¢X are set by controlling the deposition parameters. The properties of the c-axis 23¢X-tilted ZnO thin films are investigated by X-ray diffraction and scanning electron microscopy. The frequency response is measured using an HP8720 network analyzer with a CASCADE probe station. The TFBAR devices with 23¢X-tilted ZnO thin films display shear and longitudinal resonant modes at 752.75 MHz and 1.70 GHz, respectively. The mechanical quality factors (QL for longitude mode and QS for shear mode) are thus the important parameters of dual-mode TFBAR devices used in liquid environments. QL decreased from 545 to 0 upon in liquid loading, whereas QS remained almost unchanged at 296 in all environments. Moreover, the sensitivity of the shear mode to liquid loading is calculated to be 13 Hz cm2/£gg.

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Elétrica, 2007. / Submitted by Luis Felipe Souza (luis_felas@globo.com) on 2008-11-25T16:43:41Z No. of bitstreams: 1 Dissertacao_2007_CarlosEvangelistaJunior.pdf: 4060941 bytes, checksum: 0412bca1e07872e3de59fc9a31fc007d (MD5) / Approved for entry into archive by Georgia Fernandes(georgia@bce.unb.br) on 2009-02-09T11:43:11Z (GMT) No. of bitstreams: 1 Dissertacao_2007_CarlosEvangelistaJunior.pdf: 4060941 bytes, checksum: 0412bca1e07872e3de59fc9a31fc007d (MD5) / Made available in DSpace on 2009-02-09T11:43:11Z (GMT). No. of bitstreams: 1 Dissertacao_2007_CarlosEvangelistaJunior.pdf: 4060941 bytes, checksum: 0412bca1e07872e3de59fc9a31fc007d (MD5) / A crescente demanda por serviços de telecomunicações, sobretudo comunicações sem fio, e o congestionamento do espectro de radiofreqüências têm motivado o desenvolvimento de novos dispositivos de microondas com melhor desempenho e tamanho reduzido. Os ressoadores dual-mode são dispositivos com características altamente desejáveis dentro deste contexto, sobretudo por sua contribuição na redução de tamanho e peso. No presente trabalho, será estudada sua aplicabilidade na confecção de filtros. Inicialmente será realizado o modelamento do anel ressoador para a determinação de suas freqüências de ressonância. Em seguida, será feita uma análise comparativa das diferentes estratégias de alimentação desse ressoador. Por fim, serão estudados o modelamento e as topologias de estruturas com anéis ressoadores dual-mode e sua aplicação na construção de filtros. As simulações apresentadas ao longo deste trabalho foram realizadas por meio de um software que implementa o método das Diferenças Finitas no Domínio do Tempo (FDTD – Finite Difference Time Domain). Foi construído e medido um protótipo de filtro utilizando ressoadores dual-mode para consolidar o trabalho e validar o software na prática. ______________________________________________________________________________________ ABSTRACT / The increasing demand for telecommunications services and the congestion of the radio frequencies spectrum have motivated the development of new devices with performance improved and small dimensions. This work will focus on dual-mode ring resonators and its applicability on the issue of assembly of filters. Initially, the model of the ring resonator and its resonance frequencies has been studied. Afterwards, a comparative analysis of different strategies of feeding have been made. Finally it has been studied the modeling of the structures with dual-mode rings resonators and a filter with this topology have been assembled. The simulations of this dissertation had been made by a developed software which implements the Finite Difference Time Domain method (FDTD).

One-Dimensional modeling of dual mode scramjet and ramjet flowpaths is a useful tool for scramjet conceptual design and wind tunnel testing. In this thesis, modeling tools that enable detailed analysis of the flow physics within the combustor are developed as part of a new one-dimensional MATLAB-based model named VTMODEL. VTMODEL divides a ramjet or scramjet flow path into four major components: inlet, isolator, combustor, and nozzle. The inlet module provides two options for supersonic inlet one-dimensional calculations; a correlation from MIL Spec 5007D, and a kinetic energy efficiency correlation. The kinetic energy efficiency correlation also enables the user to account for inlet heat transfer using a total temperature term in the equation for pressure recovery. The isolator model also provides two options for calculating the pressure rise and the isolator shock train. The first model is a combined Fanno flow and oblique shock system. The second model is a rectangular shock train correlation. The combustor module has two options for the user in regards to combustion calculations. The first option is an equilibrium calculation with a "growing combustion sphere" combustion efficiency model, which can be used with any fuel. The second option is a non-equilibrium reduced-order hydrogen calculation which involves a mixing correlation based on Mach number and distance from the fuel injectors. This model is only usable for analysis of combustion with hydrogen fuel. Using the combustion reaction models, the combustor flow model calculates changes in Mach number and flow properties due to the combustion process and area change, using an influence coefficient method. This method also can take into account heat transfer, change in specific heat ratio, change in enthalpy, and other thermodynamic properties. The thesis provides a description of the flow models that were assembled to create VTMODEL. In calculated examples, flow predictions from VTMODEL were compared with experimental data obtained in the University of Virginia supersonic combustion wind tunnel, and with reported results from the scramjet models SSCREAM and RJPA. Results compared well with the experiment and models, and showed the capabilities provided by VTMODEL. / Master of Science

The primary purpose of this study was to test the predictions of the Dual-mode theory using arm ergometry as the exercise modality. It was hypothesized that changes in affect during exercise would be greater in high (105% GET) and low (80% GET) intensity exercise conditions than in a control condition, while differences in affect would be observed between exercise conditions. In addition, it was predicted that during recovery, there would be no differences in affect between the exercise conditions. Study participants were 24 physically active men. A within-subjects design was used. Affect was measured using the Activation-Deactivation Adjective Check List (Thayer, 1986) and the State Anxiety Inventory (Spielberger et al., 1970). Cognitive (i.e., self-efficacy, enjoyment) and physiological (i.e., heart rate, pain, perceived exertion) mediators of the exercise-affect relationship were also examined. Results showed that during exercise, changes in affect were greater in the exercise conditions than the control condition, and affective valence in the exercise conditions declined relative to the control condition. In partial support of the Dual-mode theory, self-efficacy mediated the relationship between below GET exercise and affect, whereas pain mediated the relationship between above GET exercise and affect. During recovery, arousal was higher in the exercise conditions compared to control, affective valence was less positive compared to control, and state anxiety did not differ across conditions. Finally, there were no significant differences between the two exercise conditions on any of the affect measures. These findings highlight the importance of exercise intensity to the affective benefits of exercise. / Thesis / Master of Arts (MA)

Ce travail traite une investigation systématique des performances du procédé membranaire cyclique par séparation gazeuse. Premièrement, l'état de l'art du procédé membranaire cyclique, les problèmes techniques et la modélisation du transfert à travers la membrane ont été exposés. Deuxièmement, les études théoriques et expérimentales existantes sur le procédé cyclique sont passées en revue. Selon la durée de pression haute et sa fraction dans un cycle, ce genre d'opération est divisé en deux classes: classes courte et longue. D'après cette classification, une analyse systématique de l'intérêt potentiel de la classe courte par rapport aux performances d'une opération en régime permanent a été accomplie par des simulations et optimisations numériques. Par ailleurs, afin d'améliorer la performance, l'usage du MMM dans un tel procédé a été discuté. En parallèle à l'étude sur la classe courte, une nouvelle conception du procédé cyclique de classe longue a été proposée. Les avantages spectaculaires par rapport aux procédés membranaires classiques ont été mis en évidence à l'aide de nos simulations et optimisations. Finalement, une validation expérimentale a été effectuée afin de fournir un support solide à cette nouvelle conception / This study deals with a systematic investigation of the performance of cyclic membrane gas separation processes. First, a state of the art of membrane separation processes, including material challenges and mass transfer modeling issues is proposed. In a second step, a review of the different theoretical and experimental studies performed on cyclic processes is reported. With respect to the length of the high pressure stage and its fraction in one cycle, these operations are classified into short and long classes. Based on this classification, a systematic analysis of the potential interest of short class compared to steady-state operation performances has been achieved by means of numerical simulation and optimization. In order to improve the performance, the use of MMM in such a process has been further discussed. In parallel with the short class study, a design of novel long class has been proposed. Spectacular advantages with respect to classical membrane-based processes have been highlighted by means of our simulation and optimization studies. Finally, an experimental verification has been performed in order to provide a solid support to this novel process

No description available.

Esta dissertação de mestrado apresenta uma metodologia de projeto de filtros de microondas planares passa-faixa tipo patch dual-mode, que associam baixas perdas nos condutores, boa capacidade de potência, rejeição da banda de segunda harmônica e miniaturização. Utilizou-se a ferramenta computacional MATLAB para desenvolver programas de cálculo de dimensões de ressoadores patch single-mode em função da freqüência fundamental e do substrato escolhido, bem como para cálculo da distribuição de campos eletromagnéticos (EM) ao longo destes ressoadores. O simulador EM 3D Momentum/ADS foi utilizado na análise, otimização e simulação do desempenho dos filtros. A metodologia desenvolvida consiste no projeto do ressoador patch single-mode nas geometrias quadrada, triangular e circular, com perturbações tais que resultem na freqüência central e banda de passagem desejadas para o filtro, bem como na miniaturização do mesmo. A metodologia engloba a análise do posicionamento das linhas de entrada e de saída para excitação dos modos desejados e seu acoplamento ao ressoador projetado. Foram propostos três ressoadores patch com topologias originais, modificados pela inserção de fendas, os quais foram aplicados ao projeto, construção e caracterização de cinco filtros. Desses, dois filtros passa-faixa dual-mode de banda mediana utilizam a nova topologia proposta de ressoador patch quadrado. Esses filtros, com dois e com quatro pólos, operam em 2,4 GHz e 2,35 GHz, com banda de passagem fracional de 14% e 9,8%, respectivamente. Outros dois filtros passa-faixa dual-mode de banda estreita, um com dois pólos e outro com quatro pólos, utilizam a topologia original proposta de ressoador patch triangular, com fenda em forma de \"T\" invertido. O filtro com dois pólos opera em 7,8 GHz, com banda de passagem fracional de 4,3% e o filtro de quatro pólos, em 7,5 GHz, com banda de 3,5%. Por fim, o filtro passa-faixa circular banda larga utiliza o ressoador patch circular proposto, que foi modificado para operar como triple-mode, comportamento inédito na literatura internacional enfocando ressoadores patch. Esse filtro triple-mode com três pólos apresenta freqüência central de 2,4 GHz e banda fracional de 29%. Os resultados experimentais validam a aplicação da metodologia, que apresenta grande flexibilidade no projeto de filtros com bandas estreitas, medianas ou largas, com boa rejeição na faixa de segunda harmônica (resultados acima de 13 dB). Conseguem-se leiautes miniaturizados com redução em área maior que 50% e ao mesmo tempo sem dimensões críticas, o que resulta em facilidade de fabricação através de métodos tradicionais de fotogravação em placas de circuito impresso. / This dissertation presents a methodology for the design of microwave planar bandpass filters using dual-mode patch resonators, which have low conductor loss, high power handling, second harmonic band rejection and miniaturization. MatLab software was used to develop routines that can calculate the dimensions of the single-mode patch resonators as a function of their fundamental frequency and of the chosen substrate. Further, these routines are able to calculate the electromagnetic (EM) field patterns across these resonators. Momentum/ADS EM 3D software was used for the analysis, optimization and simulation of the performance of the filters. The developed methodology consists on the design of the single-mode patch resonator in either square, rounded or triangular shape with perturbations that result in the desired filter\'s central frequency and bandwidth, and also in its miniaturization. The methodology involves the positioning of the input and output transmission lines to excite the desired modes and their coupling to the developed resonator. Three patch resonators were proposed with novel topologies that were modified by the insertion of slots, and applied to the design, fabrication, and measurements of five filters. Out of these five filters, two are dualmode medium band filters that use the proposed new topology for the square patch resonator. These filters, with two and four poles, are centered at 2.4 GHz and 2.35 GHz, with fractional bandwidth of 14% and 9.8%, respectively. Other two filters are dual-mode narrowband filters, a two-pole and a four-pole, that use the original topology proposed for the triangular patch resonator with a \"T\"-shaped slot. The two-pole filter is centered at 7.8 GHz with fractional bandwidth of 4.3%, whereas the four-pole filter is centered at 7.5 GHz with 3.5% of bandwidth. The last filter is a broadband circular filter that uses the proposed circular triplemode patch resonator, which is a brand new behavior in the international literature that focus on patch resonators. This triple-mode filter with three poles is centered at 2.4 GHz with fractional bandwidth of 29%. Experimental results validate the methodology, which presents wide filter design flexibility with narrow, medium or broad bands, and good second harmonic rejection (results better than 13 dB). Layouts can be designed with more than 50% of area reduction, and without critical dimensions at the same time, resulting in a simple fabrication that utilizes conventional PCB photopatterning process.

Esta dissertação de mestrado apresenta uma metodologia de projeto de filtros de microondas planares passa-faixa tipo patch dual-mode, que associam baixas perdas nos condutores, boa capacidade de potência, rejeição da banda de segunda harmônica e miniaturização. Utilizou-se a ferramenta computacional MATLAB para desenvolver programas de cálculo de dimensões de ressoadores patch single-mode em função da freqüência fundamental e do substrato escolhido, bem como para cálculo da distribuição de campos eletromagnéticos (EM) ao longo destes ressoadores. O simulador EM 3D Momentum/ADS foi utilizado na análise, otimização e simulação do desempenho dos filtros. A metodologia desenvolvida consiste no projeto do ressoador patch single-mode nas geometrias quadrada, triangular e circular, com perturbações tais que resultem na freqüência central e banda de passagem desejadas para o filtro, bem como na miniaturização do mesmo. A metodologia engloba a análise do posicionamento das linhas de entrada e de saída para excitação dos modos desejados e seu acoplamento ao ressoador projetado. Foram propostos três ressoadores patch com topologias originais, modificados pela inserção de fendas, os quais foram aplicados ao projeto, construção e caracterização de cinco filtros. Desses, dois filtros passa-faixa dual-mode de banda mediana utilizam a nova topologia proposta de ressoador patch quadrado. Esses filtros, com dois e com quatro pólos, operam em 2,4 GHz e 2,35 GHz, com banda de passagem fracional de 14% e 9,8%, respectivamente. Outros dois filtros passa-faixa dual-mode de banda estreita, um com dois pólos e outro com quatro pólos, utilizam a topologia original proposta de ressoador patch triangular, com fenda em forma de \"T\" invertido. O filtro com dois pólos opera em 7,8 GHz, com banda de passagem fracional de 4,3% e o filtro de quatro pólos, em 7,5 GHz, com banda de 3,5%. Por fim, o filtro passa-faixa circular banda larga utiliza o ressoador patch circular proposto, que foi modificado para operar como triple-mode, comportamento inédito na literatura internacional enfocando ressoadores patch. Esse filtro triple-mode com três pólos apresenta freqüência central de 2,4 GHz e banda fracional de 29%. Os resultados experimentais validam a aplicação da metodologia, que apresenta grande flexibilidade no projeto de filtros com bandas estreitas, medianas ou largas, com boa rejeição na faixa de segunda harmônica (resultados acima de 13 dB). Conseguem-se leiautes miniaturizados com redução em área maior que 50% e ao mesmo tempo sem dimensões críticas, o que resulta em facilidade de fabricação através de métodos tradicionais de fotogravação em placas de circuito impresso. / This dissertation presents a methodology for the design of microwave planar bandpass filters using dual-mode patch resonators, which have low conductor loss, high power handling, second harmonic band rejection and miniaturization. MatLab software was used to develop routines that can calculate the dimensions of the single-mode patch resonators as a function of their fundamental frequency and of the chosen substrate. Further, these routines are able to calculate the electromagnetic (EM) field patterns across these resonators. Momentum/ADS EM 3D software was used for the analysis, optimization and simulation of the performance of the filters. The developed methodology consists on the design of the single-mode patch resonator in either square, rounded or triangular shape with perturbations that result in the desired filter\'s central frequency and bandwidth, and also in its miniaturization. The methodology involves the positioning of the input and output transmission lines to excite the desired modes and their coupling to the developed resonator. Three patch resonators were proposed with novel topologies that were modified by the insertion of slots, and applied to the design, fabrication, and measurements of five filters. Out of these five filters, two are dualmode medium band filters that use the proposed new topology for the square patch resonator. These filters, with two and four poles, are centered at 2.4 GHz and 2.35 GHz, with fractional bandwidth of 14% and 9.8%, respectively. Other two filters are dual-mode narrowband filters, a two-pole and a four-pole, that use the original topology proposed for the triangular patch resonator with a \"T\"-shaped slot. The two-pole filter is centered at 7.8 GHz with fractional bandwidth of 4.3%, whereas the four-pole filter is centered at 7.5 GHz with 3.5% of bandwidth. The last filter is a broadband circular filter that uses the proposed circular triplemode patch resonator, which is a brand new behavior in the international literature that focus on patch resonators. This triple-mode filter with three poles is centered at 2.4 GHz with fractional bandwidth of 29%. Experimental results validate the methodology, which presents wide filter design flexibility with narrow, medium or broad bands, and good second harmonic rejection (results better than 13 dB). Layouts can be designed with more than 50% of area reduction, and without critical dimensions at the same time, resulting in a simple fabrication that utilizes conventional PCB photopatterning process.